A flesh-eating drug called Krokodil, because it makes user’s skin scaly and green before it rots away, has arrived on American soil. The Banner Poison Control center in Arizona has reported the first two users of the drug — which has been available in Russia for more than a decade — here in the U.S.

Krokodil most closely resembles morphine or heroin and is injected into the veins. It is made of codeine, a painkiller often used in cough syrup, and a mix of other materials including gasoline, paint thinner, and alcohol.

“As far as I know, these are the first cases in the United States that are reported,” Dr. Frank LoVechhio, co-medical director at Banner Good Samaritan Poison and Drug Information Center in Arizona, told CBS 5. “So we’re extremely frightened.”

When it is injected, the drug rots the skin by rupturing blood vessels, causing the tissue to die. As a result, the skin hardens and rots, sometimes even falling off to expose the bone. ”These people are the ultimate in self-destructive drug addiction,” Dr. Ellen Marmur, chief of dermatological and cosmetic surgery at Mount Sinai Medical Center in New York City told Fox News, “Once you are an addict at this level, any rational thinking doesn’t apply.”

Could a once-a-month alcoholism shot keep some of the highest-risk heroin addicts from relapse? A drug that wakes up narcoleptics treat cocaine addiction? An old antidepressant fight methamphetamine?

This is the next frontier in substance abuse: Better understanding of how addiction overlaps with other brain diseases is sparking a hunt to see if a treatment for one might also help another.

We're not talking about attempts just to temporarily block an addict's high. Today's goal is to change the underlying brain circuitry that leaves substance abusers prone to relapse.

It's "a different way of looking at mental illnesses, including substance abuse disorders," says National Institute on Drug Abuse Director Dr. Nora Volkow, who on Monday urged researchers at the American Psychiatric Association's annual meeting to get more creative in the quest for brain-changing therapies for addiction.

Rather than a problem in a single brain region, scientists increasingly believe that psychiatric diseases are a result of dysfunctioning circuits spread over multiple regions, leaving them unable to properly communicate and work together. That disrupts, for example, the balance between impulsivity and self-control that plays a crucial role in addiction.

These networks of circuits overlap, explaining why so many mental disorders share common symptoms, such as mood problems. It's also a reason that addictions - to nicotine, alcohol or various types of legal or illegal drugs - often go hand-in-hand with post-traumatic stress disorder, depression, schizophrenia and other mental illnesses.

So NIDA, part of the National Institutes of Health, is calling for more research into treatments that could target circuits involved with cognitive control, better decision-making and resistance to impulses. Under way:

-Manufacturer Alkermes Inc. recently asked the Food and Drug Administration to approve its once-a-month naltrexone shot - already sold to treat alcoholism - to help people kick addiction to heroin and related drugs known as opioids.

-Studies at several hospitals around the country suggest modafinil, used to fend off the sudden sleep attacks of narcolepsy, also can help cocaine users abstain.

-An old antidepressant, bupropion, that's already used for smoking cessation now is being tested for methamphetamine addiction, based on early-stage research suggesting it somehow blunts the high.

Medication isn't the only option. Biofeedback teaches people with high blood pressure to control their heart rate. O'Brien's colleagues at Penn are preparing to test if putting addicts into MRI machines for real-time brain scans could do something similar, teaching them how to control their impulses to take drugs.

He opened his eyes, but saw nothing. It was the middle of the night, and he was facedown in the sands of western Iraq. His loaded M16 was pinned beneath him.

Cataldi had no idea how he'd gotten to where he now lay, some 200 meters from the dilapidated building where his buddies slept. But he suspected what had caused this nightmare: His Klonopin prescription had run out.

His ordeal was not all that remarkable for a person on that anti-anxiety medication. In the lengthy labeling that accompanies each prescription, Klonopin users are warned against abruptly stopping the medicine, since doing so can cause psychosis, hallucinations, and other symptoms. What makes Cataldi's story extraordinary is that he was a U. S. Marine at war, and that the drug's adverse effects endangered lives — his own, his fellow Marines', and the lives of any civilians unfortunate enough to cross his path.

In deploying an all-volunteer army to fight two ongoing wars, in Iraq and Afghanistan, the Pentagon has increasingly relied on prescription drugs to keep its warriors on the front lines. In recent years, the number of military prescriptions for antidepressants, sleeping pills, and painkillers has risen as soldiers come home with battered bodies and troubled minds. And many of those service members are then sent back to war theaters in distant lands with bottles of medication to fortify them.

According to data from a U. S. Army mental-health survey released last year, about 12 percent of soldiers in Iraq and 15 percent of those in Afghanistan reported taking antidepressants, anti-anxiety medications, or sleeping pills. Prescriptions for painkillers have also skyrocketed. Data from the Department of Defense last fall showed that as of September 2007, prescriptions for narcotics for active-duty troops had risen to almost 50,000 a month, compared with about 33,000 a month in October 2003, not long after the Iraq war began.

In other words, thousands of American fighters armed with the latest killing technology are taking prescription drugs that the Federal Aviation Administration considers too dangerous for commercial pilots.

Military officials say they believe many medications can be safely used on the battlefield. They say they have policies to ensure that drugs they consider inappropriate for soldiers on the front lines are rarely used. And they say they are not using the drugs in order to send unstable warriors back to war.

Yet the experience of soldiers and Marines like Cataldi show the dangers of drugging our warriors. It also worries some physicians and veterans' advocates.

Prescription drugs can help patients, Dr. Broder says, but they can also cause drowsiness and impair judgment. Those side effects can be dealt with by patients who are at home, she says, but they can put active-duty soldiers in great danger. She worries that some soldiers are being medicated and then sent back to fight before they're ready.

According to Colonel Ritchie, military officials have concluded that many medicines introduced since the Vietnam War can be used safely on the front lines. Military physicians consider antidepressants and sleeping pills to be especially helpful, she says. Doctors have also found that small doses of Seroquel, an anti-psychotic, can help treat nightmares, she says, even though the drug is not approved for that use.

The U. S. Army's suicide rate is now at an all-time high. Colonel Ritchie says officials are studying the reasons for the increase, including the possible role of medications. Soldiers taking antidepressants have killed themselves, she says, but so far there is no evidence that the risk is higher for those taking the drugs.

Instead, the army has found, soldiers who committed suicide often had personal problems, such as troubled marriages or financial difficulties. Repeated deployments can strain family relationships. "The army has been at war for a long time," Colonel Ritchie says, "and everyone is kind of tired."

Pentagon policy requires that service members with psychiatric conditions be stable for at least 3 months before they can be deployed. Colonel Ritchie says she can't comment specifically on any soldier's medical history, but agrees that sending someone to Iraq just hours after leaving a psychiatric hospital would violate the policy.

Military physicians can be swayed by the aggressive promotional efforts of the pharmaceutical industry just like civilian doctors often are. The military has rules that limit the handouts doctors can take from drug companies. A doctor can go to a dinner paid for by a drug company, but the meal's value can't be more than $20, and the value of all gifts received from a company over the course of a year can't exceed $50.

The drug companies have devised ways of working around those limits.

When thousands of military and federal health-care professionals met in November for the annual meeting of the Association of Military Surgeons of the United States (AMSUS), more than 80 pharmaceutical companies and other health-care firms were on hand. The companies helped pay for that San Antonio event in exchange for the opportunity to set up booths in the convention hall, where sales reps pressed doctors to prescribe their products or to use their medical equipment and devices.

Aggressive corporate promotion is one reason behind the army's fast-rising use of narcotic painkillers. Manufacturers of narcotics like OxyContin and Actiq have spent millions in recent years to convince doctors that the drugs aren't as addictive or as dangerous as most people believe. Before such corporate marketing campaigns, many doctors hesitated to prescribe narcotics unless a patient was suffering from a serious, pain-inflicting condition — terminal cancer, for instance. Drugmakers expanded the market by encouraging docs to prescribe narcotics to people suffering from more moderate pain, and by downplaying the drugs' addictive potential.

These same manufacturers fund organizations like the American Pain Society. The society's noble goal of eliminating pain has made it the perfect conduit for drug marketing.

Military doctors agreed with the American Pain Society that pain treatment should be more accessible. In 1999, the Department of Defense and the Veterans Health Administration began a campaign called "Pain as the Fifth Vital Sign," a motto that had been created and trademarked by the society. Doctors treating active-duty service members and vets were urged to test and treat pain just as they would blood pressure and body temperature.

The Defense Department and the Department of Veterans Affairs also issued a guideline in 2003 that directed doctors on how to prescribe narcotic painkillers for chronic pain. Chronic pain can be related to conditions ranging from arthritis to the phantom-limb pain experienced by amputees. "Repeated exposure to opioids in the context of pain treatment only rarely causes addiction," the guideline noted.

That statement is controversial. In a study at Brigham and Women's Hospital, in Boston, 22 percent of patients taking narcotics for long-term treatment showed signs of abusing the drugs. The army has plenty of firsthand evidence of how addictive the painkillers can be. At Fort Leonard Wood, in Missouri, officials charged more than a dozen soldiers with illegally using and distributing narcotics, including drugs they'd reported picking up at the base's pharmacy for little or no cost. Many of the soldiers had suffered injuries in Iraq or in training but had later begun abusing the painkillers reportedly prescribed by army doctors.

One problem is that injured soldiers in pain are often also suffering from posttraumatic stress disorder (PTSD), which makes them vulnerable to abusing alcohol or drugs. A soldier taking a narcotic can start using it to escape more than his pain.

According to Colonel Ritchie, painkillers can help soldiers do their jobs by reducing pain, which allows them to concentrate. "But these medications are lethal in overdose and can't be used carelessly," she says, adding that if side effects interfere with a soldier's ability to perform, he or she is moved to another job or sent back to a home base.

The army is adding safeguards to reduce the chance that soldiers will become addicted to painkillers, she notes. And the guideline informing doctors that the drugs rarely cause addiction is being rewritten.